TABLE 3.
The distribution and correlation of air pollutants’ mean level during the 3 months before conception and the 3 months after conception (Association between maternal exposure to SO2 and congenital ear malformations in offspring: a population-based case-control study in Liaoning Province, China, 2010–2015).
| Air pollutant (μg/m3) | Exposure window | Cases (n = 1676) | Controls (n = 7950) | Correlation coefficients | ||||
|---|---|---|---|---|---|---|---|---|
| Mean ± SD | Median (25tile-75tile) | Mean ± SD | Median (25tile-75tile) | SO2 | NO2 | PM10 | ||
| SO2 | The 3 months before conception | 47 ± 38 | 35 (22–63) | 48 ± 41 | 34 (23–59) | 1 | 0.50 | 0.71 |
| NO2 | 34 ± 10 | 34 (28–41) | 37 ± 9 | 36 (31–42) | 1 | 0.50 | ||
| PM10 | 88 ± 24 | 86 (71–101) | 93 ± 27 | 89 (75–105) | 1 | |||
| SO2 | The 3 months after conception | 47 ± 36 | 35 (23–63) | 47 ± 42 | 30 (21–65) | 1 | 0.56 | 0.78 |
| NO2 | 35 ± 10 | 34 (28–41) | 37 ± 9 | 35 (31–42) | 1 | 0.53 | ||
| PM10 | 88 ± 25 | 86 (70–101) | 91 ± 28 | 87 (68–106) | 1 | |||
Abbreviations: SD, standard deviation; tile, percentile.